Predictive factors for the effect of pirfenidone in idiopathic pulmonary fibrosis

Background: Pirfenidone is one of the anti-fibrotic drugs used for patients with idiopathic pulmonary fibrosis. Pirfenidone exerts anti-inflammatory effects by inhibiting the influx of inflammatory cells. Objectives: The purpose of this study was to clarify the differences in the baseline parameters in responsive and unresponsive patients, and to assess the clinical and radiological changes after pirfenidone therapy. Methods: Patients with idiopathic pulmonary fibrosis who were treated with pirfenidone from April 2009 to March 2014 were retrospectively analyzed. The enrolled patients were classified into a good response group if they showed inhibition of progression, or were classified into a slowly progressive group on the basis of a decline in the vital capacity over a six-month interval after beginning treatment. The parameters of pulmonary function tests and laboratory findings were compared before and after treatment. The chest computed tomography findings were evaluated using the Sumikawa score. Results: Twenty patients were classified into seven good responders and eight cases with inhibition of progression. These groups had higher antinuclear antibody and autoimmune antibody values, and less ground glass attenuation at baseline. A chest computed tomography assessment at six-months after beginning pirfenidone administration showed a reduction of the ground glass attenuation findings in the good response group and an increase in airspace consolidation in the slowly progressing group compared with the baseline. Conclusions: Higher positive values for antinuclear antibodies and autoimmune antibodies at baseline and the location of ground glass attenuation at baseline, which indicates inflammatory lesions, may predict the efficacy of pirfenidone. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 290-299).